XC90 2.5L AWD - Runs Like a Dog When Hot

WellingtonX · Post by **WellingtonX** » 02 Aug 2012, 06:08

Guys
My XC90 is running poorly especially when hot. Surges, poor pick up in power. I get the Engine Service Required alert but this does clear itself after a few days. Have had the codes run and get 1210 mass air flow senor flow too high (replaced MAF but no change), 216c - long term fuel tank bank signal too high, 1200 MAF signal too high. From the forum it seems to indicate a vacuum leak but myself and my mechanic cannot find it. Latest trip to mechanic (engine mount replacement) I asked him to try to find the leak again. No joy but he reported excessive movement in the exhaust cam shaft sprocket on start up. Reported movement up to 10 mm. The mechanic is not a Volvo mechanic and was not sure if this was normal in the 2.5L but thought it could be cause of the poor performance. I can't find any reference to movement so can anyone advise me if this sort of movement is normal. Also if anyone has ideas about the codes? Many thanks.

Post by **jimmy57** » 02 Aug 2012, 08:59

The codes are consistent with a cracked intercooler or split intercooler hose.
He is seeing the exh cam sprocket move laterally 10mm? That is a new one on me.

WellingtonX · Post by **WellingtonX** » 04 Aug 2012, 05:16

Jimmy57. Thanks for responding. I took the intercooler hoses off today - all except the one under the manifold. I couldn't visually see any splits but I was surprised that the rubber hose that joins the rigid plastic hose that runs across the top of the engine and the intercooler was covered in old oil residue. Took a effort to clean up and it was similar to the residue inside the hose. I thought I had found the problem but after cleaning couldn't see anything like a split or hole. The hose was really soft. Much softer than a radiator hose. I was wondering if this hose could actually collapse under load being so soft and then could restrict flow into the turbo. PS I am ignoring the exhaust Cam spocket movement for the timebeing.

Rocky · Post by **Rocky** » 04 Aug 2012, 06:38

How many miles? You did a good thing cleaning up the inter cooler hose. Anything like that which helps the engine breath properly has to help. But if oily residue is inside the pipe, that makes me ask if the PVC system us due for servicing.
Since it runs badly only when hot and is low on power, I would want to check fuel pressure is ok.
Pull the plugs are they ok? Run some Techron on the next tank.
Just trying to knock off the cheapest items first.

Post by **jblackburn** » 04 Aug 2012, 08:58

WellingtonX wrote:Jimmy57. Thanks for responding. I took the intercooler hoses off today - all except the one under the manifold. I couldn't visually see any splits but I was surprised that the rubber hose that joins the rigid plastic hose that runs across the top of the engine and the intercooler was covered in old oil residue. Took a effort to clean up and it was similar to the residue inside the hose. I thought I had found the problem but after cleaning couldn't see anything like a split or hole. The hose was really soft. Much softer than a radiator hose. I was wondering if this hose could actually collapse under load being so soft and then could restrict flow into the turbo. PS I am ignoring the exhaust Cam spocket movement for the timebeing.

Hold your foot firmly on the brake with the car in drive and hit the gas for no more than 3-5 seconds and see if it's collapsing. It's actually pretty common among the 5 cyl turbo models.

WellingtonX · Post by **WellingtonX** » 09 Aug 2012, 04:34

Whoops last one got away from me....Try again

Guys

I thought I'd provide an update. Took the XC90 to my brother in law who is a mechanic running high performance cars but not a lot of Volvo experience. He advised the following and I'd appreciate views:

1. O2 sensor working OK for a while but when car runs rough at idle the sensor voltage is inactive

2. Thinks there may a transmission fault when it appears to clunk back to first gear and is hesitating to a large degree for the 2nd/3rd shift

To answer Rocky's post - car has done 83K miles and I had the PVC components replaced around 3 months ago as my first attempt to get this car running better. The PVC system was very dirty. I've also replaced two broken engine mounts and the harsh clunks have gone appearing to reveal he transmission clunks in point 2 above.

Here's my plan
- Replace the soft hose in the intercooler system
- Replace the oxygen sensors ( I believe there are two)
- Have the transmission opened up (yikes could be nasty)

I'd appreciate any feedback on the new information and any comments on my plan.

Cheers

Post by **jblackburn** » 09 Aug 2012, 07:17

Before you bother having the transmission taken out, try a few drain and fills of the fluid to get new fluid in there.

Your car takes JWS 3309 Volvo fluid or Toyota type IV.

WellingtonX · Post by **WellingtonX** » 06 Oct 2012, 05:18

I wanted to close this thread and let folks know that after a flush of the gearbox it is running much better. No slipping anymore. It's not the smoothest box I've had (a '94 940 GL Wagon I have is smooth as silk) but for the time being it is behaving.

Finally, I found out the original codes were all related to the front oxygen sensor. The codes from the mechanics machine didn't provide all the information but from another website I got the clue I needed which linked back to the fault above "O2 sensor working OK for a while but when car runs rough at idle the sensor voltage is inactive". I replaced with a Bosch sensor and Oxygen sensor socket and car is running better. I have a couple more things to attack and have just put up a request for help with a leaking PTC valve grommet.

Thanks for the advice. It has been outstanding and much appreciated.

WellingtonX · Post by **WellingtonX** » 27 Oct 2012, 15:30

I have been able to improve the car's performance even more since what I thought was going to be the final post. Intercooler Hoses. At one time I did get a single turbo code. I checked the system for leaks and noticed that the rubber hose going into the intercooler near the dip stick was very soft. It was covered in an oily sticky residue and I had thought that it must have a hole in it or loose clamps. I cleaned it up but there were no holes I could see. I think the oily residue was probably from the dip stick vapours that can be forced out if the PVC system is blocked. Mine was and replaced about a year ago. I replaced Hoses 2 and 4 on the standard diagram. Hose 2 is between the intercooler and the large black pipe that runs across the top of the engine. Hose 4 is smaller and at the other end. I was less worried about this one and it was only $10 so hey why not. Replacement is quite simple. My wife who drives the car commented on improvements but was unaware that I had changed the hoses. Its been excellent for some weeks now. The gearbox changes are smoother - no clunks. I figure that low pressure turbo on the 2.5 L model kicks in at low RPM and this hose must have been collapsing as it was so soft and restricting airflow. Anyway, the hoses are quite cheap and it does seem to have helped. Regards

WellingtonX · Post by **WellingtonX** » 15 Apr 2013, 16:49

For follow up to this chain please go to the following post P0101 , P2188